well whats ok regarding dates is entirely up to you and how you feel
I dont think there are norms about plutonic dates.
personally i think there are a lot of people looking for a connection that they enjoy and adds positively to their life, I also think we put to many rules and 'games' in about how we should act or what the best way to approach is.
all the games do is limit our options and make things more difficult, if you are always going to wait to be asked then you are limiting yourself to those guys that are confident enough to ask AND happen to be in the right frame of mind at exactly the time they see you.
So socially acceptable? I think as long as you are honest and friendly then its socially acceptable. If they cant see past that then chances are its not a good option anyway
Both mid 30s, 2 young kids BD 7sep14 XW moved on long ago, now living with OM1 D paperwork in progress